[Ridolenai]

I apologize for how this may sound, but please bear with me as I'll make it short and sweet.
 
I have a tendency to over research things, and have done that this time.  I want a decent pair of headphones, but have researched for an hour or so a day for the past month (sometimes up to 3-4 at a time) and have only served to confuse myself more.  I need decent quality portable (at least somewhat isolating as I don't do well in crowds and will be walking around campus).  I have narrowed it down to the following in no particular order:
 
Sennheiser:  HD 598 or HD 580
 
Audio-Technica:  ATH M50x
 
Beyerdynamic:  DT-770 (32-ohm as I will be using these on an iPod)
 
Philips Fidelio X1
 
If I am mistaken in choosing these for some reason, or if you have another suggestions that would be a better alternative in a similar price range, please let me know.  I sincerely appreciate any help that you are willing to offer, and will patiently await any response.

 

[Za Warudo]

None of these are portable except for the M50x.  The Senn and Philips are open headphones and the Beyer is too large, doesn't fold, and has a long, nondetachable cable.  So it seems like you didn't do nearly enough research.

 

[Ridolenai]

My definition of portable must be different from the generally accepted one.  By portable I meant that I could put them in a case and they would be okay in my backpack, not that they must fold.  My entire adult life until now has been spent moving every 2-3 years with my job, so I just used in-ear models, but now I want to get a decent pair of more traditional headphones.  I apparently didn't research them well enough, and I apologize for my premature posting.  As I said, I was thoroughly confused, and was unsure how much sound would leak from the open-backed headphones.  Thank you for clarifying that, I will go dig around some more for better choices.  

 

[Za Warudo]

No problem, I carry around a full sided headphone in my backpack all the time as well, but it can fold and has a short detachable cable.  Being closed is important unless you only listen in quiet environments without anyone else near you.  Also you don't want to be dragging around a heavy 6 feet cable while you are walking.

 

[Ridolenai]

In the interest of me not going blind on looking at 45 headphones again, do you have any recommendations on closed-back headphones that might fit the use necessary?  I am considering the M50X, but it appears to be made fairly inexpensively, and I don't know how well it would hold up.

 

[Za Warudo]

The M50 has a reputation for being durable.  No need to worry about that.
 
These factors are most important for portability:
-Closed: isolation and no leakage of sound
-Cable: has to be short (3-4 ft ideal) and preferably detachable, coiled cables are no good
-Size: depends on your preferences but can't be too big and preferably foldable
-Easy to drive: depends on your source.  Unless you use a portable amp or a DAP with a built in amp, the headphone need to be low impedance and high sensitivity.  All headphones designed for portable use are easy to drive.
 
I would look at these guides and lists for recs:
http://www.head-fi.org/a/buying-guide-headphones-by-price-range
http://www.head-fi.org/a/a-hopefully-helpful-headphone-buying-guide-for-newbies-by-boomana
http://www.head-fi.org/a/head-fi-buying-guide-introduction
http://www.innerfidelity.com/content/innerfidelitys-wall-fame-full-size-sealed
 
for IEMs:
http://www.head-fi.org/t/478568/multi-iem-review-328-iems-compared-lear-luf-4f-luf-4b-luf-4c-added-11-07-14-p-994